I am thinking of having a 9mm barrel made that is 16" in length and .936/1" at the muzzle so i can use a DPMS bull barrel A2 front site.  then having it backbored so there is only 10" of rifling.  anyone had this done or seen it done, what are your thoughts?  I am also leaning towards assembling it in dissipator format.  anyone done this or seen a 9mm AR dissipator?  

It's going to be heavy, but can be done. Why not just go SBR route?  Making a barrel for the 9mm Colt pattern is straight forward though.

If you're concerned about sight radius buy a match rear and front sight aperture, or pick up a nice dot sight.  I had problems with grouping too but then I tried the above.  Made a big difference.

my plan is to thin the front 6" out as much as possible and to flute the 10" over the rifling. this should reduce the weight enough.  I also like the A2 length handguards more.  it isn't really a sight radius issue.  i do plan on building an SBR, but i am in the process of moving back to MN from CA.  the prob is that i will be moving to an interim apt there.  i want to wait til i find a more permanent place before i start the process.  also if i find a couple of places i'm more likely to get the place with a "friendly" CLEO.